Bearing arrangement with a shaft and a needle bearing

Abstract

A bearing arrangement is provided having a shaft ( 1 ) with a bearing journal ( 2, 3 ), and a needle bearing ( 9 ) which is arranged thereon and has a cage ( 16 ) and needle rollers ( 11 ) accommodated in the latter. The bearing journal is provided with a hardened and precision-machined inner raceway ( 10 ) for the needle rollers and steps back radially in relation to axial shoulders ( 12, 13 ) of adjacent shaft sections ( 4, 5, 6, 7 ), and the axial shoulders serve as run-on surfaces for the axial end sides ( 14, 15 ) of the cage fitted between the axial shoulders. In this case, relief grooves ( 17, 18 ) are provided, with the relief grooves extending on both sides of the inner raceway and each being dimensioned in such a manner that, over the entire circumferential region of the axial shoulders, the axial distance (D) thereof from each other is significantly larger than the inner raceway width (B 1 ) existing therebetween.

The invention claimed is: 
     
       1. A bearing arrangement comprising a shaft having a bearing journal integral with the shaft and having a needle bearing that is situated on the bearing journal and having a cage and needle rollers accommodated therein, the bearing journal is a hardened and precision-machined inner raceway for the needle rollers that is offset radially inwardly at least over part of a circumference thereof relative to axial shoulders of adjacent shaft sections of the shaft, the axial shoulders acting as run-on surfaces for axial end faces of the cage fitted between the axial shoulders, wherein relief grooves are provided that extend on both sides of the inner raceway and are each dimensioned such that over an entire circumferential region of the axial shoulders their axial distance from one another is significantly greater than a width, situated between the relief grooves of the inner raceway. 
     
     
       2. The bearing arrangement as recited in  claim 1 , wherein the shaft is an unbalanced shaft having a center of gravity that is eccentric to an axis of rotation, the inner raceway being essentially stationary relative to an unbalanced load that loads the inner raceway in a load zone, and the load zone extends within a circumferential region, which is significantly less than 360° , of the axial shoulders. 
     
     
       3. The bearing arrangement as recited in  claim 2 , wherein the circumferential region of the axial shoulders is greater than 170° and less than 190° . 
     
     
       4. The bearing arrangement as recited in  claim 2 , wherein the inner raceway has a width that changes over a portion of a circumference of the inner raceway, and that, extending out from the load zone, the width tapers axially inwardly toward a center of the inner raceway outside the load zone or is interrupted. 
     
     
       5. The bearing arrangement as recited in  claim 1 , wherein the inner raceway is precision-machined by honing. 
     
     
       6. The bearing arrangement as recited in  claim 1 , wherein the width of the inner raceway between the axial shoulders is greater than a length of the needle rollers, the cage being penetrated by openings that are distributed around a circumference thereof and that extend axially on both sides of the needle rollers.